Seat AUDI A8 2003 D3 / 2.G Technical Features Manual

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Introduction
The new Audi A8 is designed to replace its
predecessor of the same name which achieved
a total production figure of 105,092 since its
introduction in June 1994. This was the first
standard saloon with aluminium body and
epitomised a new philosophy in the luxury
vehicle sector.
The weight-saving Audi Space Frame ASF
represented a major breakthrough in terms of
enhanced vehicle dynamics, whilst at the same
time solving the problem of increasing weight.
Introduction
This body concept was further perfected in
the Audi A2 and the design of the Audi A8 ´03
reflects the experience gained from both
projects.
The aim when developing the Audi A8 ´03 was
not merely to surpass its predecessor in
terms of technical features and details.
Convenience/infotainment control
via multimedia interface (MMI)
3.7 or 4.2 l V8 engine
with intake manifold
changeover function
Adaptive cruise control (ACC)
with radar sensor
in front bumper
Headlight with adaptive
light functionActive head restraints
for front seats

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Rear end
The rear end has been completely
redeveloped. The two large central castings
are the one connecting the sill panel/
longitudinal member and the C/D-pillar
connecting element.
SSP282_032
The C/D-pillar connecting element (large
upper casting) accommodates the
suspension strut at the top and the seat belt
at the front, in addition to forming the
terminating side section of the roof frame.
The large upper and lower castings are
interlinked by way of two straight extruded
sections and form the framework for the air
suspension strut holder.
SSP282_033
The sill panel/longitudinal member
connecting element is the largest casting. It
supports the entire rear sub-frame and links
the rear longitudinal member to the sill panel.
Its great rigidity is designed to protect the
tank in between in the event of a rear-end
collision.
Large upper castings
Extruded sections
Large lower castings

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Seats
A new seat concept was developed for the
Audi A8 ´03.
The basic seat features the following
standard functions:
– Electric seat length, height and angle
adjustment
– Electric backrest angle adjustment
– Front crash-active head restraints (refer to
Page 21)
The basic seat can additionally be fitted with
– Four-way lumbar support
– Seat memory for driver and front
passenger
– Electrically adjustable head restraints
– Electric belt height adjustersExtra features of sports and comfort seats:
– Electric top 1/3 backrest adjustment
– Electric seat depth adjustment
Optional extras for comfort seat:
– Climate function (refer to Page 85)
– and/or massage function
The massage function is implemented by way
of rhythmic action of the electromechanical
lumbar support, thus massaging and relaxing
the back muscles.
The fixed rear seat bench versions correspond
to those of the front seats, with the third head
restraint being fully retractable. Electric
individual seats are however only available as
"Basic" and "Comfort" versions.
SSP282_116
Crash-active, electronic
head restraint with 70 mm height
adjustment
Thorax/pelvis
side airbag
Backrest fan
Seat cushion fan Electric seat depth adjustment – As the
structure moves forwards it pulls the
padding with it and so extends the seat
area by 50 mm. Backrest adjustment –
The angle of the top
1/3 of the
backrest can be adjusted by 15°
for enhanced shoulder comfort.
Lumbar support with massage
function over a length of 60 mm

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Active head restraints
The front seats of the Audi A8 ´03 are provided
with active head restraints.
With this system, the head restraints move
forwards in the event of a rear-end collision to
shorten the distance between head and
restraint.
SSP282_082
The danger of cervical vertebrae injury is
greatly diminished by reducing the relative
acceleration between shoulder and head.
In head-on collision situations, the mechanics
of centrifugal weight are neutralised.
Belt tensioners
Five belt tensioners are fitted as standard.
There is no centre belt tensioner if the rear
seats are electrically adjustable.

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Bus topology
Electrical System
The increasing demand for additional
functions and convenience in the vehicle calls
for the use of ever more wide ranging
electronics.
The increased use of electronics also requires
a new approach to data transfer between the
individual control units. This also applies to
the Audi A8 ´03, in which more than 70 control
units have to communicate.
Distance regulation
control unit J428
Electric park and
handbrake control
unit J540Headlight range
control unit
J431Airbag control unit
J234ABS with EDL
control unit
J104
Engine control unit
J623Adaptive
suspension control
unit J197 Engine control
unit 2 J624Automatic gearbox
control unit
J217
Anti-theft/
tilt system control
unit J529
Boot lid control unit
J605Wiper motor control
unit J400Garage door
operation control
unit J530 Multifunction
steering wheel
E221
Convenenience
system central
control unit J393On-board power
supply control unit
J519
On-board power
supply control unit 2
J520Steering column
electronics control
unit J527Steering angle
sender G85
Driver side door
control unit J386Front passenger
side door
control unit J387Rear left door
control unit J388Rear right door
control unit J389Seat adjustment
control unit
J136Front passenger
seat adjustment
control unit J521 Control unit with
display in dash panel
insert J285
Diagnostic connection T16
Dash panel insert CAN
Drive system CAN
Diagnosis CAN
Convenience CAN
Internal bus link
LIN
Adaptive cruise control
CAN

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Telephone/
telematics control
unit J526
Front information
display and operating
unit control unit J523Rear DVD changer
R162Telephone
handset
R37
Control unit for rear
left
information display
and operating
unit J648
DSP control unit
J525
Navigation system
control unit
J401
TV tuner
R78
Digital radio
R147
Radio module R Chip card reader
control unit
J676 CD changer
R41 CD ROM drive
R92 Data bus diagnostic
interface J533
Fresh-air blower
control unit
J126Heated windscreen
control unit J505Rear left footwell
heater element Z42Rear right footwell
heater element Z43Driver seat
ventilation
control unit J672Front passenger
seat ventilation
control unit J673

Parking aid control
unit J446 Entry and start
authorisation
control unit J518 Energy
management
control unit J644 Rear seat
adjustment with
memory control
unit J522 Climatronic control
unit J255
Trailer detector
control unit J345
Rear Climatronic
control and
display unit E265Tyre pressure
monitor control unit
J502
Sun roof electronics
control unit J528
Additional heater
control unit J364Driver identification
control unit J589
Auxiliary heating
radio controlled
receiver R64 Sliding sun roof
motor V1 Front passenger
side rear seat
ventilation
control unit J675 Driver side rear seat
ventilation control
unit J674 Control unit for rear
right
information display
and operating
unit J649
MOST busBluetooth
TM
LIN
LIN

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An optional feature for the Audi A8 ´03 is
4-zone climate control, enabling both driver
and all passengers to make individual
settings independently of the climate control
level selected for the other occupants.
Design and operation
The air conditioning system represents a
more advanced version of the concept
employed in the Audi A8 predecessor model
with 2-zone climate control and features fully
automatic regulation.
Heating/Air Conditioner
The following components are new features
as compared to the systems previously fitted
in the Audi A8:
– Humidity sender G355
– Evaporator outflow temperature sender
G263
– Two versions: 2-zone front climate control
with 12 control motors and 4-zone front
and rear climate control with 15 control
motors
– Rear climate control with electric rear
additional heater as additional equipment
("4-zone system") – rear left and rear right
footwell heater element Z42 and Z43
– Second control and display unit with
4-zone climate control, Climatronic control
unit J255, rear Climatronic control and
display unit E265– Climate control menu in MMI (Multimedia
Interface) for display of climate control set
values and basic settings
– Front and rear seat heating and seat
ventilation
– Heated windscreen Z2
– Energy management control unit J644
The interaction of these components in
coordination with the entire air conditioning
system forms a control loop and permits
comfortable front and rear climate control to
suit all requirements.
SSP282_098

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A distinction is made between two air
conditioner unit versions
– 2-zone front and rear climate
control
– 4-zone front and rear climate
control
and three types of control and
display unit
– Air conditioner control panel with
no seat heating/ventilation
– Air conditioner control panel with
seat heating
– Air conditioner control panel with
seat heating and seat ventilation
(identified by part number index).
SSP282_099
Self-diagnosis
Fault diagnosis and measured value blocks
for air conditioner and seat heating system
can be read out by way of address words 08
"Air conditioner/heater electronics" and 28
"Rear climate control". The functions of and
exact procedure for self-diagnosis and
assisted fault-finding with VAS 5051 can be
found in the Heating/Air Conditioner
Workshop Manual for the relevant vehicle
model.
Operating principle
When the ignition is switched on, the
Climatronic control unit J255 starts up with
the same temperature, air distribution and
fresh-air blower speed settings etc. as were
applicable the last time the ignition was
switched off by way of the appropriate key or
using fingerprint recognition.
If fingerprint recognition has been
implemented, this has priority over key
recognition (refer also to SSP 287 – Audi A8 ´03
Electrical Components).
Personalised settings
The following settings can be made for each
climate control zone (front left, right and,
optionally, with 4-zone climate control rear left
and right):
– Left/right temperature
– Air flow
– Left/right air distribution
– Left/right seat heating
– Left/right seat ventilation
– Operating modes (AUTO for driver and front
passenger, temperature-adjustable centre
vents, automatically controlled
recirculated-air mode, ECON)
The heated windscreen can be activated by
way of the air conditioner defrost button or
the air conditioner control unit automatically
switches on the electric heated windscreen if
the appropriate conditions are satisfied
(windscreen defrost or automatic mode on
cold starting).
The Climatronic J255 and heated windscreen
J505 control units communicate by way of the
LIN bus. The Climatronic control unit transmits
the specified windscreen heating power to the
heated windscreen control unit on the LIN bus.
Heating/Air Conditioner
Key recognition takes place in the case of
remote control (radio or key transponder),
with the driver identification control unit
providing the Climatronic control unit J255
with the appropriate information by way of
the CAN bus.
The electrically heated windscreen is only
supplied with the amount of power which can
currently be drawn from the electrical system
without draining the battery. This is
monitored by the energy management
control unit J644.
As is the case with the Audi A4, the
windscreen is heated by applying voltage to a
metallic foil fitted in the glass (refer to
SSP 213).
As in the Audi A4, the air conditioner
compressor is regulated as a function of load
and controlled externally by way of the
compressor regulating valve (refer to
SSP 240). The Climatronic control unit J255 is
connected to the convenience CAN, via
which diagnosis is also performed.
A manual air conditioning system is not
available.

Downloaded from www.Manualslib.com manuals search engine Climatronic control unit J255
SSP282_100
Rear Climatronic control and display unit E265
Air conditioner basic setting
control
Heated rear window
control Front control panel
activation/
deactivation
Seat ventilation
control
Air distribution control
– Up
– Chest vent/centre
– Down Left rotary control/pushbutton
Rotary control +/- for
– Temperature
– Blower speed
– Air distribution up/down
– Seat heating
– Seat ventilation
– Menu control via MMI
Pushbutton
– Synchronisation of driver's
side, passenger's side and
rear settingsDriver's side
control panelPassenger's side
control panel Seat heating controlReset to basic setting/
automatic mode
Temperature sensor
with blowerAir conditioner defrost
and electrically heated
windscreen
Manual recirculated-air
mode control Blower control
Rear left
control panelCentre console/footwell
air distribution controlReset to basic setting/
automatic mode
Rear right
control panel
Left rotary control/pushbutton
Rotary control +/- for
– Temperature
– Chest vent and footwell air
distribution
– Seat heating
– Seat ventilation
Pushbutton
– Synchronisation of driver's
side and passenger's side
settings
Rear left seat heating
controlRear control panel
activation/
deactivation
Rear right seat
ventilation controlRear right seat heating
control
Rear left seat ventilation
control

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3
36
Auto
21,5° C
63
3
The current air conditioner settings are stored
automatically and assigned to the
appropriate remote control key. On vehicles
with Audi one-touch memory (optional), the
current setting is also assigned to the
corresponding fingerprint. Air conditioning system control via MMI
All air conditioning system set values and
basic settings (setup) can be displayed by
way of the MMI. This applies both to the
Climatronic control unit button functions and
to setup.
If the air conditioning system is activated
with the MMI switched on, the air conditioner
function settings can be called up and altered
by way of the multimedia control panel. The
functions indicated in the corners of the
displayed mask are activated using the
softkeys.
Basic setting (setup)
The basic air conditioner settings can only be
altered when the MMI is active. This involves
pressing the SETUP button on the Climatronic
control unit.
The following functions can be selected:
– ECON ON/OFF
– Automatic air recirculation active/inactive
– Synchronisation active/inactive
– Centre vent (temperature-adjustable)
settings between - 3 and + 3
– Auxiliary heater active/inactive
– Auxiliary ventilation active/inactive
– Auxiliary heater/ventilation operating time
15 min./30 min./45 min./60 min.
– Auxiliary heater/ventilation timer status for
timers T1, T2, T3 ON/OFF
– Solar mode active/inactive (solar cells
C20)
– Rear control ON/OFF
The desired settings can be called up and
altered with the driver's/front passenger's
control knob on the Climatronic control unit.
SSP282_112
SSP282_113
low high
Econ
Distribution Seat ventilation
Blower Seat heatingAC - driver
Blower Seat heatingAC setup
Distribution Seat ventilation
Off
Autom. air recirculationOff
Synchron.Off
Centre vent